Locomotive cooling system



y 1947- 1'. B. DILWORTH 5T M. 2,423,929

LOCOMOTIVE COOLING SYS'I'EI random. 5, 1945 2 Sheets-Sheet 1 flame:- 01720032 Jlf 0' 6. 14770 y 5 T. B. DILWORTH ET AL 2,423,929

- LOCQHOTIVE COOLING SYSTEM Filed Oct. 5, 1945 w 2 Sheets-Sheet 2 I 3nvntou v 2 J 5 3., mzmzzazaaz z'az nas 6 01711101:

Patented July 15, 947

LOCOMOTIVE COOLING SYSTEM Thomas B. Dilworth, Hinsdale, and Milo M. Schalla, Oak Lawn, IlL, assignors to General Motors Corporation, Detroit, Mich, a corporation of Delaware Application October 5, 1945, Serial No. 620,582

6 Claims. (01. 105-35) The present invention relates to generating electric locomotive cooling systems of the temperature responsive type,

The principal object of this invention is to provide a simple automatic locomotive cooling system including a plurality of engine cooling radiators, radiator shutters and motor driven cooling fans adapted to operate at a speed proportional to that of the engine and engine tem-' perature responsive means for causing opening of the shutters and starting of the motors in different sequence each time the engine warms up and for causing simultaneous closure of the shutters and shut down of the fan motors when the engine cools down so that the engine operates within the most efficient operating temperature range for wide variations in load, ambient temperature and head, side and tail winds encountered by the locomotive.

The combination and arrangement of means by which the above object is accomplished will become apparent by reference to the following detailed description and drawings illustrating one combination of cooling and control means which is particularly adapted for generating electric locomotives.

Figure l of the drawings is a vertical elevation view of a locomotive with parts broken away to show the arrangement of certain of the engine cooling and control means to good advantage.

Figure 2 is a cross sectional elevation view taken on line 22 of Figure 1.

Figure 3 is a schematic view of the operating means for and details of the shutters for controlling the engine cooling radiator air.

Figure 4 is a schematic view and wiring diagram of the electric cooling fan drive and temperature responsive control means for the fan motors and radiator shutter operating means.

As best illustrated in Figure 1 the locomotive comprises a cab supported-on two multi-axle articulated traction trucks 3. The power generating unit located within the cab includes an internal combustion engine 5 directly connected to an electric traction generator I for supplying power to the traction motors, not shown, driving the axles of the trucks 3. A three phase alternator 9 is directly connected to the traction generator 1 for supplying power at frequencies proportional to the engine speed.

A service opening is provided in the arcuate roof or the cab I above the engine 5 and a sheet metal hatch cover generally indicated at H covers this opening as best illustrated in Figures roof portion. l3, vertical transverse end walls I5 and vertical transverse partitions l1 spaced longitudinally therebetween to form four separate transverse exhaust air ducts l9 and a central bottom portion 2| with longitudinal openings 23 on either side thereof. Engine cooling radiators 25 are secured over these openings to the lower edges of the end walls I5 and partitions ll of the hatch A circular exhaust air stack 21 is provided in the upper central arcuate portion of each exhaust air duct l9. An exhaust fan 29 and a three phase induction motor operably connected thereto is supported by suitable brackets in each hatch exhaust duct It! so that the fan 29 is located adjacent the exhaust stack 21. The four induction motors are indicated at MI to M4. As best illustrated in Figure 2 when the hatch cover II is in place the engine cooling radiators are positione'd above and extend along each side of the cab I andengine 5 and slope upwardly and inwardly to the central bottom portion 2| of the hatch cover Longitudinally extending radiator air inlet openings 33 are provided in opposite 1 and 2. The hatch cover includes an arcuate 55 sides of the cab directly below each radiator and radiator shutters 35 having overlapping shutter vanes 31 pivoted about vertical axes are provided to normally close each of the radiator air inlet openings. A pneumatic shutter cylinder 39 is secured to each cab side between the openings 33 and each cylinder is provided with aplunger 40 which is connected to the shutter vanes 31 adjacent thereto by suitable links and levers as shown in Figure 3. Each of these cylinders 39 also includes a plunger retracting spring 4| to normally urge the shutter vanes 31 to the closed position as best shown in Figures 3 and 4. An electropneumatic shutter control valve 43 is connected between an air pressure reservoir and the shutter cylinders by pipes 41 and 49. The shutter valve 43 when deenergized relieves the pressure in the cylinders 39 so the plunger retracting springs 4| cause closure of the shutter vanes 31. When the shutter valve 43 is energized air pressure is applied to the shutter cylinders 39 and plungers 40 from the reservoir 45 to cause opening of the shutter vanes 31.

A longitudinal air baflle 5| is hinged along the lower edge of the radiator inlet air openings 33 in either side of the cab and chains 53 support these baiiles 5| from the hatch so that they slope upwardly and inwardly from the cab sides toward the central bottom portion 2| of the hatch leaving a small air entrance opening therebetween so that some air may be drawn from the interior of the cab I through the radiam a by the fans 2|. on air entrance opengine, driven alternator s. It will be evident with A 4 warms up. The shutters are caused to open at the lowest value or temperature in the temperature range in which the engine operates eiliciently and the shutters are closed and all of the fans I are shut down when the engine temperature falls below this lower value temperature in response to action of the temperature responsive switching means I1 located in the engine outlet water manifold is.

the above arrangement that when the shutters As best illustrated in Figure 4 the tempera.-

" are open and the fans 2'! and induction motors MI, m, M! and MI are operating radiator coolin! air is drawn in through the radiator inlet openings 39 and radiators 29 into the hatch'exhaust ducts I9 and exhausted outwardly therecentral exhaust air stacks 21 therein.

A radiator water outlet manifold 99 is connected between the outside lower corners of the radiators II at one end thereof and the upper portion of an engine oil cooler 6|. A small diameter branch pipe '93 i connected between the manifold 59 and the upper portion of a water storage and make-up tank 95. The lower end of the engine oil cooler 9| is connected to an inlet pipe 91 or an engine driven water cooling pump 99, the outlet pipe II of which is connected to the coolant space around the cylinders and cylinder heads of the engine 9. The lower end of the tank 90 is connected by a small diameter branch pipe-I9 to the pump inlet pipe 61. The engine I is provided with an upper engine outlet water manifold ll, including temperature responsive switching mechanism, generally indicated at IT in Figures land 4. The .manifold II is connected to the upperouter corners of the engine cooling radiators at the opposite ends thereof. The level of the water in the englhe cooling system including the oil cooler 9| and storage tank 95 is normally maintained at' a the engine cylinder heads when the engine and cooling pump 99 is stopped. when the engine 5 and pump 69 is operating water is circulated thereby longitudinally through the radiators 29 and back through the engine oil cooler BI to the pump ,99 and to and through the engine 5 as this is the path 01. least water flow resistance. however some water passes from the radiators 29 through the higher flow resistance-path to the pump 69 through the tank 95 and smaller diameter branch pipes 93 and I9 which connect the storage and make-up tank 69 in parallel with the oil cooler 9|. With the above described piping system when the engine 0 and cooling D p 69 is stoppcd the water in the radiators 25 drains downwardlyinto the engine coolant space and engine oil cooler 9| and storage tank 99 to the normal level thereby eliminating the danger of freezing and damage to the radiators in cold weather.

The cooling air drawn through the radiators by operation of three of the four motor driven fans 29 is sufiicient to prevent overheating oi the engine in hot weather when operating under full load and operation of all four fans 29 prevent engine overheating under extreme high ambient temperature conditions such as encountered in tunnels when the engine is operating at full load and the Diesel locomotive unit is operated behind a steam locomotive or in multiple behind similar units. As previously explained the radiator inlet air shutters 95 are opened and the tan driving motors MI-Ml are caused to ture responsive switching means I1 is included in a control circuit which includes the electropneuinatic shutter valve 43, a battery 19, a current relay 8|, sequence relays 83 and 85 of idenlIi tical form and fan motor contactors 81, 89, 9| from by the exhaust fans 29 through the upper and 99 which are also of identical form and connected by power conductors, shown in heavy lines, between the engine driven alternator 9 and each of the induction motors MI to M4 drivgo ing the exhaust cooling fans 29 for controlling includes a thermally expansible element 95 secured at one end to a stationary member 96 in I the engine outlet water manifold 15 and having a stepped contact bar 91 secured to the other end of the element and movable thereby upon 80 warm-up of the engine into contact successively with a plurality of fixed contacts IOI, I03, I05. I09; I01 and I08 of the switch mechanism.

The current relay 8| includes two pairs of fixed contacts, an armature having contacts cooperating therewith and a contactor winding which when energized causes upward movement of the armature contacts from the normalposition as shown.

The sequence relays 99 and are provided with a contact lever I09 carrying two contact height slightly above the coolant space around bars I I0I I I and pivoted at its center and having an upstanding "central finger I I2 with notches on either side thereof and an armature and armature winding which when deenergized causes the armature to drop to the position shown. A pawl H3 is pivoted on the lower end of the armature and whenthe armature falls the pawl engages one or the other of the sides of the upstanding central finger II2 of the con- 5 tact lever I09 depending upon which way it is tilted, and enters one or the other of the notches adjacent the finger to cause the contact lever to be tilted in theopposite direction. When the contact lever I09 is in the position shown each of the contact bars IlIlIII thereon contacts a separate contact finger of a pair located adjacent one end of the contact lever. Energizatlon of the winding causes the armature to be pulled up and the pawl H3 pivoted thereon ac- 00 cordingly assumes a vertical position. When the l winding is next deenergized the armature and pawl falls and the upstanding control finger II! of the contact lever I09 guides the pawl into whichever lever 'notch that is rocked upwardly B5 so-that the weight of the falling armature and pawl causes the contact lever to be tilted in the opposite direction. This causes each of the contact bars IIOI II of the contact lever I09 to be rocked to the opposite position into contact with one contact finger of another pair of fingers located adjacent the other end oi the contact lever.

The motor contactors 81, 89,. -9I and 93 are provided with three pairs 0! fixed power contacts each pair of which is connected by power operate in different sequence each time the engine conductors, shown in heavy lines, between one locking contacts and an armature having power and interlocking contacts is moved upwardly "to the motor operating position from the normal position shown upon' energization of contactor windings H4 and H4. The winding H4 serves as a holding Winding and is energized to hold the armature in the motor operating position.

The following battery excitation, control and interlocking connections are shown extending between the battery, temperature responsive switching means, contactors, relays and electropneumatic shutter valve.

The positive terminal of the battery 19 is connected by positive conductors II5H6 to one terminal of an excitation winding HI of the alternator 9, the'fixed contact I9I of the temper- "ature responsive switching means 11 and one of the upper normally open pair of fixed contacts of the current relay BI. The negative battery terminal is connected by negative return conductors H8, H9 and I29 to the other winding terminal of the alternator excitation winding II'I, one terminal of each of the relays and contactors and one winding terminal of the electropneumatic shutter valve 43. The other upper fixed contact of the current relay BI is connected by conductors I2I. I22 and I23 to the other winding terminals of the sequence relays 83 and 85 and the shutter valve 43 and also to one of the lower normally open pair of fixed interlock-' ing contacts of each of the motor contactors 81, 89, 9I and 93. f

The stepped contact bar 91 of the temperature responsive switching means TI. is connected by a flexible conductor I24 to one of the lower pair of fixed contacts of the current relay 8| and the other contact of this pair is connected to a conductor I25 which is connected between the other winding terminal of the relay 8| and the fixed contact I93 of the temperature responsive switching means 11-,

The fixed contact I95 of the switching means is connected by a conductor I29 to a conductor I21 interconnecting the upper left and lower right contact fingers of the sequence relay 83. The upper right and lower left contact fingers of the relay 83 are interconnected by a conductor I28 which is connected by a conductor I29 to the fixed contact I98 of the switching means. The upper contact bar H9 of the relay 83 is connected by a 1 flexible conductor I39 and a conductor I3I to the right-hand fixed interlocking contacts and the -other terminal of the holding winding H4 of the motor contactor 93. The other fixed interlocking contact ofthe normally closed upper pair of the contactor 93 is connected by a conductor I32 to the other terminal of the other contactor winding I I4. The lower contact bar III of the sequence relay 83 is connected by a flexible conductor I33 and a conductor I34 to the right-hand fixed interlocking contacts and other terminal of the holding winding H4 of the motor contactor 81. The other fixed interlocking contact of the normally closed upper pair of the contactor 81 is connected by a conductor I35 to the other terminal of the other winding H4 thereof.

The fixed contact I96 of the temperature responsive switching means 11 is connected by a 6 the switching means I1 is connected by a conductor I38 to a conductor I39 interconnecting the left lower and right upper contact fingers of the sequence relay 85. The upper contact bar I I9 of the relay is connected by a flexible conductor I49 and a conductor I4I to the right-hand fixed interlocking contacts and other terminal of the holding winding H4 of the motor contactor 9I, the fixed upper left interlocking contact of which is connected by a conductor I42 to the other terminal of the other holding winding H4 of the contactor 9I. The lower contact bar III is connected by a flexible conductor I43 and a conductor I44 to the right-hand fixed interlocking contacts of the contactor 89, the fixed upper left-hand interlocking contact of which is connected by a conductor I45 to the other terminal of the other winding II4 thereof.

'As previously explained when the engine 5 isstopped and-cold the water in the radiators 25 has drained back-into the engine coolant space, oil cooler BI and-water storage and make-up tank 65 to the normal level slightly above the coolant space around the engine cylinder coolant space and the temperature responsive switching means, relays and fan motor contacts are in the position shown so that the radiator inlet air shutters 35 a are closed and the fan motors MI-M4 arev stopped. The excitation winding I I1 of the alternator 9 is energized as it is connected across the battery 19 by conductors H6 and H8.

When the engine 5 is started the engine driven cooling pump 69 causes circulation of cooling water throughthe engine coolant space, radiators 25 and oil cooler BI and some water, as explained, is circulated through the tank 65. When the traction generator 1 driven by the engine 5 is supplying full load current to the traction motors and the engine is operating at maximum speed the output frequency of the engine driven alternator is proportional to the engine speed.

Upon an increase in the temperature of the cooling water circulating in the engine outlet manifold 15 to a given value slightly below the minimum value in 'the temperature range in which efilcient operation of the engine occurs, the thermally expansible element 95 of the temperature responsive switching means 11 expands and causes the stepped contact bar 91 to move into contact'with the fixed contact I9I of the switching means. This sets up a holding 'circuit for the winding of the current relay 8| through conductors H5 and I24. Warm-up of the engine cooling water to the minimum value in the temperature range for eflicient engine operation causes the stepped contact bar 91 to next be also moved by the expansible element 95 into contact with the fixed contact I93 of the switching means 11. This bridging of the fixed contacts IM and I93 by the stepped contact bar 91 of the switching means 11 completes an energizing circuit through conductors H5, I25 and H8 and the winding of the current relay 8| to cause upward movement of the relay armature contacts into bridging contact with the fixed relay contacts. Bridging of the upper fixed contacts of the current relay BI completes a circuit through conductors H8, I2I, I22, H9 and H8 and windings of the sequence relays 83 and 85 and the winding of the electro-pneumatic shutter control valve to cause upward movement of the sequence relay armatures and pawls I I3 pivoted thereon and the opening of the shutter control valve to cause air pressure from the reservoir 45 to flow through the valve and pipes 41 and 49 to the shutter conthereof.

- 3i and 33 by the bridging oi the upper fixed contacts of the current relay 3|. The bridging of the lower fixed contacts of the current relay completes the holding circuit comprising the conductors II! and I2! to the winding of the current relay 3i previously set up by contact between the fixed contact MI and stepped contact bar 91 of the switching means and the negative return conductor 3 connected tothe return terminal o! the relay winding.

A slightly higher value of engine outlet water temperature causes the stepped contact bar 31 of the switching means to then also be moved into contact with the fixed contact I 33 thereof. This bridging of the fixed contacts I3i and I33 completes an energizing circuit through both windings I and N3 of the motorcontactor 93 to cause upward movement of'the armature This energizing circuit includes the left upper contact finger and upper contact bar N3 of the sequence relay 83, which are in contact, and the normally closed upper fixed interlocking contacts of the motor contactor 33 and conductors I23, I21, I33, I3I, I32 and return conductor II3. Initial upward movement of the armature of the contactor 33 causes the opening of the upper fixed interlocking contacts to break the energizing circuit through the conductor I32 and contactor winding Ill and full upward movement of the contactor armature causes simultaneous closure of the three phase fixed power contacts to cause energization and the starting of the induction motor M3 and the closure of the lower fixed interlocking contacts of the contactor 33 which completes the holding circuit comprising conductors -I2I and I23 set up by closure of the upper contacts of the current relay 3| to the holding-winding I I4 01 the contactor and the'return conductor H3 connected thereto. Starting and operation of the induction motor M3 supplied from the engine driven alter-. nator causes it to drive its fan at a speed proportional to the engine and draw air through substantially one-fourth of each cooling radiator.

Should the engine water outlet temperature increase to a slightly higher value the stepped contact bar 31 of the switching means will also be moved by the thermal element '33 into contact with the fixed contact I33 of the switching means. This completes a similar energizing circuit to the windings H3 and Ill oi. the motor contactor 33 controlling operation of the fan motor M2 through the right-hand finger and upper contact her I ll) of the sequence relay 85 which are in contact and the normally closed upper interlocking contacts and conductors I36, I31, I and I35. This causes upward movement of the armature of the motor contactor 33 which causes clo- A slight further increase in the temperature of the engine outlet water to the normal full load engine operating temperature causes movement of the stepped contact bar :31 into contact with s the fixed contact I31 by further expansion or the thermal element 33 of the switching means 11. This likewise completes a similar energizing circuit to the windings oi the motor contactor II and upward movement 01' the armature thereof to cause closure or the power contacts and starting and operation of the fan motor M3 and fan driven thereby, causing cooling air to then be drawn through substantially three-fourths of the radiators 23 and to cause the opening of the upper and closure of the lower interlocking contacts which causes deenergization or the .winding Ill and maintains energizatlon oi the holding wind-- ing I I3 of the contactor 3| through the previous-- ly set up holding circuit.

Should the temperature or the engin outlet water. increase to the maximum value of temperature In the operating range due to some unusual high ambient operating temperature condition, such as operation of the locomotive unit as a following unit in a tunnel, the stepped contact I tor MI so that air is drawn through all portions of the radiators 23 to provide maximum cooling of the engine and to likewise cause the opening of the upper and closure of the lower contactor interlocking contacts to cause deenergization of the contactor winding I I3 and to maintain the holding winding 3' energized. It will be noted that with the sequence relays in the position shown the fan driving motors MI to ,M3 start in the following sequence; M3, M2, M3 and MI.

When the load is taken completely oil. the engine 3 and the temperature of the engine outlet cooling water decreases to a value below the minimum in the operating range the stepped contact bar3l is moved by the contraction of the thermal element 33 of the switching means 11- out of contact with the fixed contacts I38, I31, I33, I33, I33 and II successively. This however does not cause stopping of the fan motors operating until the holding circuit of the current relay 3| is broken by movement of the stepped contact bar out of contact with the fixed contact Ill. This causes deenergization oi the winding and the dropping of the armature of the current relay M to the position shown to break the holding circuit comprising conductors I2I and I23.to

the holding winding 3' of each of the motor contactors and to simultaneously break the energizing circuit comprising conductors I2I and I22 to the windings of the sequence relay 33 and and the electropneumatic shutter control. valve 33, to cause simultaneous stopping of all the fan motors operating and closure of the radiator air inlet shutter vanes 31. Deenerglzation oi the windings of the sequence relays 33 and 35, as previously described, causes the dropping 01 the armatures and pawls pivoted thereon into contactwith the opposite side of the upstanding.

finger M2 on the contact lever and notch adjacent thereto from the positions shown to rock the levers and contact bars H3 and III thereon to the opposite position from that shown so that upon the next warm-up of the engine the shutters 35 will be opened in identical manner to that described but as the contact leversof the seshutters opened simultaneously upon the next deenergization of the winding and dropping of the armature of the current relay 8]. When this occurs the windings of the sequence relays 83 and 85 are again deenergized to cause the contact levers to be tilted back to the positions shown by the dropping of the armatures and the pawls into the notch adjacent the upstanding finger as shown.

It will be evident that the electrical connections between thecurrent relay 8| and sequence relays 83 and 85 causes the contact lever I09 of the sequence relays to be rocked to the opposite position each time the windings of the sequence relays are deenergized by deenergization of the winding and dropping of the armature of the current relay 8| by movement of the stepped contact bar 91 out of contact with the fixed contact IOI of the temperature switching means 11 each time the engine water outlet temperature drops below the lowest valuein the range for eficient engine operation. This causes a differminimum value in order to cause sequential starting and operation of the fan motors and for causing simultaneous operating of the switching means upon a decrease in the temperature of the coolant below said minimum value in order to. cause simultaneous shut down of the fan motors operating. r

2. In combination, an engine having a coolant space and a coolant circulating pump driven thereby, a radiator connected to the engine coolant space to provide .a coolant circulating circuit, a radiator shutter having normally closed vanes to block air flow therethrough, power ent sequence of starting and operation of the fan motors each time the engine warms up to eflicient operating temperature and accordingly uniform depreciation and 'wear of the fan driving motors takes place. Furthermore reverse tilting of the contact lever and contact bar-ssecured thereto with the opposite pair of contact fingers of the sequence relays takes place only after the circuit including these contact bars and fingers is broken by deenergization of the current relay which makes and breaks the relay and contactor energizing circuits. Should the current relay stick in the closed position the sequence relays, electropneumatic shutter valve and motor contactors remain closed and when the engine load and speed is reduced the motor driven fans will continue to operate a lower speed to prevent overcooling of the engine. In addition to the above novel features should the radiator shutters stick or freeze in the closed position for any reason, cooling air will be drawn through the radiators by the fans from the engine cab or in reverse flow direction downwardly through the exhaust air stacks of the fans which are not operating.

We-claim:

1. In combination, an engine having a coolant space, a radiator connected with the coolant space to provid a coolant circulating circuit, a plurality of fans adjacent the radiator causing air flow through different portions of theradiator, fan driving means including an engine driven alternator and separate induction motors driving individual fans, power connections including separate switching means for connecting each fan motor to the alternator for operation at a speed proportional thereto and fan motor control means including means acting in response todifferent predetermined values of engine coolant temperatures above a predetermined value for eflicient operation of the engine and relays connected therewith and controlled thereby for causing sequential closing of the separate fan motor switching means upon an increase in the teinperature of the circulating coolant above said means for opening the shutter vanes, a plurality of fans for causing air flow through different portions of the radiator upon opening of theradiator shutter vanes, an induction motor for driving each fan, an engine driven alternator, power connections including separate fan motor switching means .to cause operation of the fan driving motors at a speed proportional to the engine driven alternator and control means including engine coolant temperature responsive means and sequence relays connected therewith for controlling the power means and fan motor switching means to cause opening of the shutter vanes and different sequential operation of the fan driving motors each time the temperature of th engine coolant increases above a predetermined value and for causing simultaneous closure of the shutter vanes and shut down of the fan driving motors operating each time the temperature of the engine coolant decreases below said predetermined value.

3. In combination, an engine having a coolant space, a coolant circulating pump driven thereby, an engin oil cooler, a coolant storage and makeup tank, a coolant radiator located above the engine, oil cooler and tank, means for connecting the engine radiator and oil cooler in a, low re-' sistance series coolant flow relation and means for connecting the storage and make-up tank in high resistance parallel coolant path with the oil cooler whereby upon stopping of the engine and circulation of the coolant the coolant in the radiator drains downwardly therefrom, a. radiator air shutter having normally closed vanes to prevent air flow therethrough, power means for opening the shutter vanes, a plurality of fans for causing fiow of air through difi'erent portions of th radiator, fan driving means including an engine driven alternator, separated induction motors for driving individual fans and power connections including separate fan motor switching means for connecting the engine driven alternator with one or more fan motors to cause operation of the fans at a speed proportional to the engine and shutter and fan motor control means includingmeans acting in response to the temperature ofthe engine coolant and relays connected therewith to cause sequential operation of the shutter power means and motor switching means to cause opening of the shutter vanes and different starting and operating sequence of the fan motors each time the coolant of the engine increases above a predetermined value and to cause simultaneous closure of the shutter vanes and shut down of the fan motors when the temperature of the engin coolant decreases below and a traction generator and alternator driven 11 by the engine, said cab having a roof openin a hatch covering said roof opening and including a coolant radiator connected to the engine coolant space to provide a coolant circulatingcircuit, a plurality of exhaust air openings in the hatch above the radiator, an exhaust fan adjacent each opening'ior causing air flow through a. portion of the radiator, an induction motor driving each i'an, said cab having inlet air openings in the sides. some or which are located below the radiator to serve as radiator inlet air openings, a bailie on the cab side for directing air upwardly to the radiator from the radiator air inlet openings, shutters having vanes normally closing the radiator air inlet openings, power means for opening the shutter vanes, separate power connecting means for connecting each fan motor to the engin driven alternator to cause air to be drawn through a diiierent portion or the radiator, and control means for the power operated shutter vane opening means and the fan motor connecting means including interconnected engine coolant temperature responsive control means and sequence control relays for causing opening of the radiator shutter vanes and starting and operation of the tan motors in different sequence each time the temperature or the engine coolant increases above a predetermined minimum value, and for causing simultaneous closure of the shutter vanes and shut down of the fan motors upon a decrease in the engine coolant temperature below said predetermined minimum value.

5. In a generating electric locomotive, ailocomotive cab having a root opening and side opening below the root openings and at either end, a locomotive power plant in the cab below the root opening, said power plant including an engine having a coolant space and an engine driven coolant circulating pump, a traction generator and an alternator driven by the engine, a hatch cover for the root opening in the cab, said hatch cover having longitudinal bottom openings along each side, transverse end walls and partitions iorming air ducts and exhaust stack in the roof portion of each duct, enginecoolant radiators 45 closing the longitudinal openings, and an exhaust Ian and fan driving motors of the induction type supported in each hatch opening, operation 01' certain of said fans the tan driving motors providing cooling air for the radiator; to

take care or normal full load speed conditions of the engine, shutters having normally closed 50 perature value.

vanes blocking entrance of, air through the cab side openingsbelow the radiators, power means for opening the shutter vanes, separate power connecting and switching means between each fanmotor andthe engine driven alternator and control means including engine coolant temperature responsive means, sequence and control relays connected to the shutter power means and fan motor switching means to cause opening 10 of the shutter vanes followed by sequential starting and operation of the fan motors at a speed proportional to the engine driven alternator upon an increase in the temperature of the engine coolant above a minimum value for eflicient en- 15 gine operation and for also causing simultaneous closure 01' the shutter vanes, shut down of the motors operating and operation of the sequence relays to change the subsequent starting and operation sequence of the fan motors.

go 6. A cooling system for a generating electric power plant including an engine having a coolant space, an alternating current generator driven by the engine, a power .plant hatch cover including a radiator, connected to'the engine coolant 5 space, a plurality of radiator cooling fans for causing air flow through the radiator, an induction motor driving each fan, power connections and individual contactors for each fan motor for causing each motor to be connected to the engine 30 driven alternator so that the fan are operated by the motors at a speed proportional to the engine and control means for the motor contactors and includinga source of current, a current relay, sequence relays and switching means operable at at predetermined temperature values of the engine coolant above a given minimum engine operating value so that upon 'energization and operation of the relays the motor contactors are energized in sequence to cause sequential operation of the 40 fan motors and upon deenergization' or the relays by a decrease in the engine coolant below said minimum value the motor contactors are simultaneously deenergized to cause simultaneous shut down of the fan motors and thesequen'ce relays when deenergized operate and set up difl'erent energizing connections to the motor contactors whereby a. different starting and operating sequence of the fan motors takes place each time the engine coolant exceeds said minimum tem- THOMAS B. DILWORTH. MILO M. SCHALLA. 

